We study effects of CDNF protein in the rat unilateral maximal lesion PD 6-OHDA model. CDNF is administered prior to, and two weeks after, intracranial injection of 6-OHDA into the ascending DA bundle.We study effects of CDNF protein in the mouse bilateral PD model induced by parental injection of MPTP. We study effects of CDNF protein in the MitoPark mouse model. We are developing a mouse CDNF null mutation and will study development of the midbrain DA system. We will generate AAV-CDNF and in order to test effects in the 6-OHDA rat model and in the MPTP and MitoPark mouse models. In vivo tests of such a vector, if successfully generated, will be carried out in future research.